1. Field of the Invention
The present invention relates to a collision detection sensor of an air bag device used for protecting passengers mainly during a collision of a vehicle, from the side.
2 Description of the Related Art
Recently, vehicles have been equipped with air bag devices for protecting passengers from impact by detecting a collision and immediately providing an expanded air bag as a protection measure for passengers during a vehicle collision, in addition to a seat belt device.
The conventional air bag device for protecting passengers during a head-on collision is provided at the steering wheel or a part of the instrument panel in general, to reduce impact from the front. Recently however, combined use of an air bag device that is operated corresponding to a collision from the side has been examined in order to further improve safety during a collision, and for example, a collision detection sensor for detecting a side collision from the deformation of a vehicle door has been proposed.
As for the conventional example, a collision detection sensor was proposed in which two pairs of comb-shaped electrodes are used with their contact operation parts arranged alternately, and the sensor is operated only when at least one of the contact operation parts of the respective comb-shaped electrodes, that is, both pairs of the comb-shaped electrodes are turned on (PCT/WO90/06247).
However, as this sensor is operated only when an impact force is received on an area larger than a prescribed area, the sensor might not operate when a locally large load that should be regarded as a collision, such as a collision against a pole, is received.
Recently however, combined use of an air bag device that is operated corresponding to a collision from the side has been examined in order to further improve safety during vehicle collision. Thus, development of a detecting means that can assure accurate and prompt detection of a side collision is urgently required.